By Carly Peters
Water scarcity is a world-wide concern and hits closer to home as human and industry demand increases and supply dwindles. Federated Co-operatives Ltd.’s, Co-op Refinery Complex (CRC) in Regina is looking to a sustainable future by not only reducing their water consumption, leaving more for their community to use, but reducing wastewater and air emissions through an innovative wastewater recycling and treatment process.
In 2013, the CRC completed a $2.8-billion expansion, increasing its oil production by 30 per cent to more than 130,000 barrels a day. But the expansion created a new challenge — producing more oil also meant the refinery consumed more water, potentially enough to exceed its provincially regulated allocation for withdrawals from the local aquifer. The refinery could pull water from the city of Regina, but the refinery’s leaders wanted a more sustainable solution.
The task was great as oil refining and oil upgrading are very water-intensive processes. The Regina complex uses an average of 1,500 to 1,700 gallons of water per minute, or two million gallons a day, for tasks such as generating steam, making hydrogen, and cooling. It became clear that a new approach to water use would be necessary, says Gilbert Le Dressay, the Co-op Refinery Complex’s vice-president of refinery operations.
In partnership with their technology provider, GE, the CRC designed and developed a $200-million sustainable system called the Wastewater Improvement Project (WIP). Once fully operational, the CRC will be the only refinery in North America that can clean and recycle all its wastewater for steam production.
The zero-discharge design utilizes a multi-pronged approach. Stage 1 sees the separation of oil and water by gravity in holding tanks, skimming oil off the top as it floats above the water, while during Stage 2, microscopic bubbles of nitrogen are pumped up through the water, binding with suspended oil particles and bringing them to the top of the unit where they are removed. The oil recovered in both stages is returned to the refinery for processing.
Stage 3 and 4 is where WIP moves beyond all other water recycling systems. The water moves on to a GE membrane bioreactor where specially designed bacteria break down volatile organic compounds (VOCs) and ammonia, improving the quality of the water and reducing odours associated with oil refining. It then flows through GE’s patented ZeeWeed, long spaghetti-like strings, which are in fact heavy fibre membrane technology, that remove suspended solids.
“To the eye it looks like really clean water at this point but there’s still a lot of biomass,” explains Le Dressay, adding that’s why at the next stage the water is sent to a centrifuge to separate and return the special live bacteria to the reactor, and to recover any water so that it can be fed back to the recycling process.
The system then employs high-efficiency reverse osmosis, or HERO mode, to clean wastewater for steam production. This high-efficiency method, which is certainly not a standard procedure in other refineries, ensures the water is free of any remaining solids, heavy metals, or salts that might collect on equipment and interfere with their operation.
While the benefits to the plant are apparent, it’s the community-driven results that will take the company into the future, according to Le Dressay.
“Water is a very precious resource and we did not want our refinery to be a burden on Regina’s water resources. This is a blueprint for our long-term success as a refinery. It’s also our industry finding a way to balance the work of providing energy and being environmentally and socially conscious for the community,” he says.
With the elimination of city water, the refinery’s reliance on freshwater resources will be reduced by an estimated 30 per cent or the equivalent of freeing up water usage for 3,100 homes in Regina on an annual basis. Also, since the water is recycled and returned to the plant, the refinery will have zero discharge into the city’s municipal wastewater treatment plant.
Along with the reduction in water usage and wastewater, WIP will also significantly decrease VOC emissions from the refinery’s wastewater ponds, substantially reducing the nuisance odours the refinery’s neighbours sometimes smell. Le Dressay states there will be zero discharge from the ponds once the system is fully operational.
While new technology and sustainable initiatives keep the CRC modern, Le Dressay says it’s the Co-op’s business model, which has been in place for almost 100 years, that will continue to take the company and refinery into the future.
“The co-op movement comes from a different perspective because it comes from small communities. There’s a focus on community, environmental stewardship for future generations, as well as fiscal responsibility. There is no financial recoup on WIP, it’s a break-even project but the recoup of social responsibility is huge.”
Previously published in the winter 2016 issue of We Build, the official publication of the Saskatchewan Construction Association.